EFFLORESCE, v.t. efflores'. [L. effloresco, from floresco, floreo, to blossom, flos, a flower. See Flower.1. In chimistry, to form a mealy powder on the surface; to become pulverulent or dusty on the surface. Substances effloresce by losing their water of crystallization.Those salts whose crystals effloresce, belong to the class which is most soluble, and crystalize by cooling.2. To form saline vegetation on the surface; or rather to shoot out minute spicular crystals; as the efflorescence of salts on plaster.